1. Field of the Invention
The present invention generally relates to computer systems, and more specifically to a method and device for installing computer components, particularly printed circuit boards or cards, such as dual in-line memory modules (DIMMs), which are mounted in slots or sockets of the computer system.
2. Description of Related Art
The basic structure of a conventional computer system 10 is shown in FIG. 1. Computer system 10 has at least one central processing unit (CPU) or processor 12 which is connected to several peripheral devices, including input/output devices 14 (such as a display monitor, keyboard, and graphical pointing device) for the user interface, a permanent memory device 16 (such as a hard disk) for storing the computer's operating system and user programs, and a temporary memory device 18 (such as random access memory or RAM) that is used by processor 12 to carry out program instructions. Processor 12 communicates with the peripheral devices by various means, including a bus 20 or a direct channel 22 (more than one bus may be provided using a bus bridge).
Computer system 10 may have many additional components which are not shown, such as serial and parallel ports for connection to, e.g., modems or printers. Those skilled in the art will further appreciate that there are other components that might be used in conjunction with those shown in the block diagram of FIG. 1; for example, a display adapter connected to processor 12 might be used to control a video display monitor, and a memory controller may be used as an interface between temporary memory device 18 and processor 12. Computer system 10 also includes firmware 24 whose primary purpose is to seek out and load an operating system from one of the peripherals (usually permanent memory device 16) whenever the computer is first turned on.
Conventional computer systems often allow the user to add various components after delivery from the factory. For peripheral devices, this can be accomplished using an "expansion" bus, such as the Industry Standard Architecture (ISA) bus or the Peripheral Component Interconnect (PCI) bus. Another component that is commonly added by the user is main memory which supplements temporary memory device 18. Additional memory, which supplements temporary memory device 18. This memory is often made up of a plurality of memory modules that can be added or removed as desired. The memory modules usually have memory chips in dual in-line packages, mounted on a single circuit board or card, and so are referred to as dual in-line memory modules (DIMMs). DIMMs can be added to upgrade a system's memory, or to replace older modules that have become defective.
Each DIMM has an edge with a plurality of contacts or pins (e.g., 72 pins), adapted to mate with a card edge connector (socket or slot). A typical DIMM 30 and socket 32 connector are shown in FIG. 2. DIMM 30 is generally comprised of a flat, rectangular substrate or card 34, supporting a plurality of memory chips 36. The body of socket 32 has a slot 38 formed therein for receiving the contact edge of DIMM 30. DIMM 30 may be conveniently retained in slot 38 using retention tabs 40 having clips which engage small notches 42 formed in the side edges of card 34. In this manner, the DIMM is latched firmly within connector 32 without possibility of accidental removal by inadvertent contact with the card, or external vibrations and impacts.
Tabs 40 are also used for ejecting card 34 from slot 38. Tabs 40 are pivotally mounted and biased to the closed, locking position, but when they are forcibly moved (with a finger or tool) to the open, unlocked position, a lower boss member (not visible in FIG. 2) attached to each tab pushes the contact edge of card 34, ejecting it out of slot 38.
DIMMs are available in different sizes, and not only with respect to physical size, but also with respect to the amount of memory that they provide. For example, DIMMs used with personal computers (PCs) often come in sizes of 16 megabytes, 32 megabytes, 64 megabytes, 128 megabytes, 256 megabytes, etc.
Within a given computer, the slot connectors for the memory modules are often arranged in two or more banks. This arrangement of memory banks is usually both physical and logical, that is, the layout of the slot connectors on the memory card or computer's primary circuit board (the "motherboard") has connectors grouped by banks, and these same groupings correspond to logical banks that are used by the hardware specific to that computer system, i.e., the memory controller. Oftentimes, it is necessary to place DIMMs in particular slots, due to the architecture of the hardware. For example, if DIMMs of different sizes (available RAM) are mixed in a single computer (e.g., several 64 megabyte DIMMs and several 128 megabyte DIMMs), it is necessary to place the particular types of DIMMs in certain respective slots. If the modules are not placed correctly, various problems may occur, such as the firmware simply not recognizing the full amount of memory that is available, which significantly impairs overall performance.
In the prior art, it is often difficult to identify which particular connector on a motherboard is to receive a new component, such as a DIMM. DIMM sockets are not clearly identified by logical group, and this lack of suitable identification presents a problem when DIMM's must be concurrently populated for the memory card to work. DIMM sockets can be identified using reference designations or silkscreen labelling on the memory card, but most often a service manual is required to determine where to plug particular DIMM's. It would, therefore, be desirable to devise a method which would eliminate the need for silkscreen labelling or other costly processes, and also remove the requirement for the customer to refer to the service manual in order to add DIMM's in the correct positions.